B2 W2 - Pathophysiology and Clinical Aspects of Asthma (LT) Flashcards

1
Q

What is the estimated prevalence of asthma in the UK?

A

10-15% of the population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the hygiene hypothesis?

A

This theory suggests that extreme cleanliness in childhood increases the likelihood of developing asthma.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name two environmental factors, aside from hygiene, that contribute to asthma development.

A

Pollution and occupational sensitizers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two main classifications of asthma?

A
  • Extrinsic (“atopic”) asthma
    and
  • Intrinsic asthma.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the typical onset age for extrinsic asthma?

A

Childhood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the typical onset age for intrinsic asthma?

A

Middle age.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the three key features of asthma pathophysiology?

A
  • Reversible airway obstruction
  • Airway hyper-responsiveness
  • Airway inflammation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

List four key features visible in a histological cross-section of a bronchiole from a patient with severe asthma.

A
  • Mucus plugging
  • Inflammatory cells infliltration (especially mast cells, eosinophils, and macrophages)
  • Hypertrophy (and hyperplasia) of smooth muscle
  • An increased number of goblet cells in the epithelium.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which cell releases histamine in a process known as ‘degranulation’?

A

Mast cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which antibody class is responsible for binding allergens and causing degranulation of mast cells?

A

IgE.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which T lymphocyte type is most important in the response to allergens in asthma?

A
  • T-helper cells type 2 (Tн2).
  • A subtype specifically implicated in allergic responses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens during the immediate/early phase of asthma pathogenesis?

A

The allergen is recognised and bound by IgE antibodies, which then bind to and activate mast cells and cause them to degranulate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the timeframe for the immediate/early phase of asthma pathogenesis?

A

0-60 minutes after allergen exposure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens during the late phase of asthma pathogenesis?

A

Chemical mediators (released by the mast cells and TH2 cells) cause

  • vascular leakage and oedema
  • Infiltration of eosinophils and neutrophils
  • Mucus secretion.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the timeframe for the late phase of asthma pathogenesis?

A

1-8 hours after allergen exposure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens during the chronic remodelling phase of asthma pathogenesis?

A

Structural changes in the airways, often referred to as airway remodelling inluding:

  • Smooth muscle hypertrophy and hyperplasia
  • Epithelial damage
  • Basement membrane thickening.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the timeframe for the chronic remodelling phase of asthma pathogenesis?

A

Months to years after the initial allergen exposure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

List four classic symptoms of asthma.

A
  • Cough
  • Wheeze
  • Chest tightness
  • Dyspnoea (Shortness of breath)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is asthma difficult to diagnose in young children?

A

Diagnostic tests like peak flow or spirometry testing are difficult to perform on young children.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

List four signs of asthma exacerbation a doctor may find on examination.

A
  • Difficulty completing full sentences
  • High respiratory rate (tachypnoea)
  • High heart rate (tachycardia)
  • Wheeze
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why might reduced breath sounds indicate a more severe asthma exacerbation?

A

They suggest very little air is moving in and out of the lungs, possibly due to airway blockage by mucus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Apart from patient history and response to treatment, list some investigations that can be used to help diagnose asthma.

A
  • Reversibility on spirometry
  • Diurnal variation on peak flow monitoring
  • Fractional exhaled nitric oxide (FeNO)
  • Blood eosinophils.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is Fractional Exhaled Nitric Oxide (FeNO)

A
  • FeNO measurement is a relatively newer non-invasive test that measures the level of nitric oxide in exhaled breath.
  • Elevated FeNO levels can indicate airway inflammation, a characteristic feature of asthma.
  • This test is particularly useful in identifying eosinophilic airway inflammation, a specific type of inflammation often present in asthma.
24
Q

What key feature on peak flow monitoring would suggest a diagnosis of asthma?

A

Diurnal variation.

25
Q

Why would blood eosinophils be used in the diagnosis of asthma?

A

Elevated blood eosinophil counts can suggest an underlying allergic or inflammatory process, supporting an asthma diagnosis.

26
Q

What is the benefit of using a patient’s normal average peak flow for monitoring?

A

It allows for comparison with measurements taken when they are unwell.

27
Q

What is the first treatment usually given for an acute asthma attack?

A

β2-agonist bronchodilators (e.g., salbutamol).

28
Q

What other treatment should all asthma attacks be treated with?

A

Corticosteroids.

29
Q

What is the minimum recommended duration for corticosteroid treatment in acute asthma?

A

5 days.

30
Q

Aside from oxygen, β2-agonist bronchodilators, and corticosteroids, list some other treatments that may be used in acute asthma management.

A
  • Ipratropium bromide
  • Magnesium sulphate (IV)
  • Aminophylline (IV)
  • Prednisolone
  • Hydrocortisone
  • Antibiotics
31
Q

What is the main aim of chronic asthma management?

A

To prevent acute exacerbations and reduce inflammatory changes that lead to airway remodelling.

32
Q

What is the recommended first-line treatment for most patients with asthma?

A

Inhaled corticosteroids (ICS).

33
Q

Name two categories of asthma inhalers and give an example of each.

A
  • Relievers (e.g., salbutamol)
  • Controllers (e.g., salmeterol).
34
Q

Why is proper inhaler technique important?

A

It ensures the patient receives the full benefit of the medication and reduces the risk of side effects from swallowing it.

Just think about the house scene

35
Q

How does the stepwise approach to managing chronic asthma work?

A
  • The approach involves assessing asthma symptoms and adjusting treatment accordingly.
  • If symptoms worsen, treatment is stepped up by adding or increasing medication.
  • Conversely, if symptoms remain well controlled, treatment can be stepped down to reduce the risk of side effects.
36
Q

What is the typical pattern of diurnal variation in asthma?

A
  • Asthma typically improves during the day and worsens overnight.
  • This is due to fluctuations in cortisol levels, which are naturally higher in the morning and lower at night.
37
Q

Why is diurnal variation important in asthma?

A
  • It is a key feature that can help diagnose asthma and assess its severity.
  • This variation is reflected in peak flow measurements, which tend to be higher in the evening and lower in the morning for asthmatics.
38
Q

What are the consequences of poor inhaler technique?

A
  • Poor inhaler technique can lead to the medication being deposited in the mouth and throat instead of the lungs.
  • This reduces the effectiveness of the treatment and increases the risk of side effects, such as oral thrush from inhaled corticosteroids.
39
Q

What is ‘mucus plugging’ in asthma?

A
  • Mucus plugging refers to the blockage of airways by thick mucus, a common occurrence during severe asthma exacerbations.
  • It can significantly hinder airflow and worsen breathing difficulties.
40
Q

Why is a ‘silent chest’ a concerning sign in an acute asthma attack?

A
  • A silent chest, where wheezing is no longer audible, indicates severely restricted airflow and is a sign of life-threatening asthma.
  • This situation requires immediate medical attention.
41
Q

What role do antibiotics play in asthma management?

A
  • Antibiotics are not routinely used in asthma management.
  • They are only prescribed if there is evidence of a bacterial infection contributing to the asthma exacerbation, such as pneumonia.
42
Q

Why is it important to manage chronic asthma effectively?

A
  • Effective management aims to prevent acute exacerbations, as frequent asthma attacks can lead to a decline in lung function and increase the risk of future severe attacks.
  • It also helps reduce the inflammatory changes that can cause irreversible airway remodelling.
43
Q

What are some examples of occupational sensitizers that can contribute to asthma?

A
  • Glues
  • Insulation material
  • Wood dust
  • Latex
  • Rat urine
44
Q

Why is it thought that children growing up on farms are less likely to develop asthma?

A

This observation is linked to the hygiene hypothesis, which suggests that exposure to a wider range of microbes in a farm environment might help to train the immune system and reduce the risk of developing allergies and asthma.

45
Q

What does the early phase of an asthma attack involve?

A
  • The early phase of an asthma attack, which occurs within the first hour after allergen exposure, involves the binding of allergens to IgE antibodies.
  • These activated IgE antibodies then bind to mast cells, leading to mast cell degranulation.
46
Q

What is the late phase of an asthma attack charecterised by?

A
  • The late phase, which happens 1-8 hours after allergen exposure, is characterized by vascular leakage and oedema.
  • This is due to the chemical mediators released by mast cells and T helper 2 (TH2) cells.
47
Q

Repetitive exposure to allergens or triggers can cause what in the asthmatic airway?

A
  • Chronic changes

These changes, part of the chronic remodelling phase, include:

  • hypertrophy of smooth muscle
  • hyperplasia of smooth muscle and epithelial cells.
48
Q

How can asthma symptoms can present differently in younger individuals compared to older individuals?

A
  • In younger individuals, particularly those with atopic asthma, asthma symptoms often coincide with other inflammatory or allergic symptoms such as hayfever or eczema.
  • This suggests a potential link between asthma and these conditions in this age group.
49
Q

What clinical sign could indicate a more severe asthma exacerbation?

A
  • Reduced breath sounds during an asthma exacerbation are a worrying sign.
  • This suggests a more severe attack because it might indicate that very little air is entering or exiting the lungs.
  • This could be due to mucus plugging, where mucus blocks the airways.
50
Q

Usually, what colour are reliever inhalers?

A

Blue

51
Q

Usually, what colour are ‘controller’ inhalers?

A

Green

52
Q

Usually, what colour are ‘preventer’ inhalers?

A

Brown/ Orange

53
Q

Usually, what colour are ‘combination’ inhalers?

A

Purple

54
Q

When is asthma considered ‘Life-threatening’?

A

Anyoneof the following, in a patient with severe asthma:

Clinical signs:

  • Altered conscious level
  • Exhaustion
  • Arrhythmia
  • Hypotension
  • Cyanosis
  • Silent chest
  • Poor respiratory effort

or

Measurements:

  • Peak flow <33% best or predicted
  • Oxygen saturations <92%
  • PaO2 <8 kPa
  • ‘Normal’ PaCO2 (4.6 - 6.0 kPa)
55
Q

When is an acute asthma attack considered severe?

A

Any one of:

  • Peak flow 33-50% best (or predicted)
  • Respiratory rate ≥25/min
  • Heart rate≥110/min
  • Inability to complete sentences in one breath